The Thomson Reuters/PayNet Small Business Lending Index rose to 141.5 from an upwardly revised March reading of 130.5.

From a year earlier, the index was up 13 percent. At the same time, the delinquency rate on loans more than 30 days past due fell in April, to 1.52 percent, suggesting the increased borrowing has not come at the expense of financial health.

It's really firming up, PayNet founder Bill Phelan said of the trend in borrowing by companies in retail, accommodations, transportation, construction, health care, professional services and other industries. It will bode well for GDP for the rest of the year.

The index has historically tracked ahead of US gross domestic product growth by two to five months.

US GDP fell at a 0.7 percent annual rate last quarter. Data since then has been mixed.

US consumer spending unexpectedly stalled in April, data released Monday showed. But manufacturing activity picked up in May for the first time in seven months and construction spending surged in April to a near 6-1/2-year high.

Even more critical than the actual data, perhaps, is how Fed officials interpret it as they prepare for a policy-setting meeting in about two weeks. There, views are nearly as mixed as the underlying data.

Boston Fed President Eric Rosengren, for instance, signaled Monday he has begun to worry about the absence of a snapback in economic growth.

San Francisco Fed President John Williams, by contrast, has stuck to his view that the slowdown is likely temporary and indeed the first-quarter economy likely will turn out not to have been as weak as currently estimated.

PayNet collects real-time loan information such as originations and delinquencies from more than 250 leading US lenders.